1. Field of the Invention
The present invention relates generally to retractable coverings for architectural openings and more particularly to a lift cord system for a retractable covering wherein the lift cord includes an endless loop of cord operably connected to the bottom rail of the covering to enable easy leveling of the bottom rail.
2. Description of the Relevant Art
Coverings for architectural openings have been used for numerous years to cover windows, doorways, archways, and the like, with such coverings assuming numerous forms and configurations. Examples of such include draperies, venetian blinds, vertical blinds, retractable shades, and the like. More recently, retractable coverings have been made with a cellular fabric for not only enhanced aesthetics but to also improve insulation across the architectural opening.
Retractable cellular coverings as well as other forms of retractable coverings typically include a top rail or headrail in which operative components of the covering are enclosed, a bottom rail and a flexible fabric or shade material extending between the top rail and bottom rail. A lift cord system is typically employed for raising and lowering the bottom rail to retract and extend the covering, respectively, with the lift cord system typically including several independent cords which are gathered in an hand-operated tassel at one end of the covering, extend through a cord lock in the top rail, across a portion of the top rail, and down through the fabric or shade material for connection to the bottom rail. In this manner, by pulling downwardly on the tassel, the bottom rail is raised and vice versa by allowing the tassel to elevate, the bottom rail can be lowered. The cord lock releasably holds the lift cords in a desired position so the covering can be fully elevated, partially elevated, or fully extended as desired.
As will be appreciated, for desired aesthetics, it is desired that the bottom rail remain parallel to the top rail during all operations of the covering and when a plurality of lift cords are utilized, it is sometimes difficult to make each lift cord of a length that allows the bottom rail to be suspended from the top rail in a parallel relationship therewith. Accordingly, systems have been devised for adjusting the effective lengths of the lift cords so the bottom rail can remain parallel with the top rail regardless of its separation therefrom. An example of a system for adjusting the effective lengths of lift cords is shown, for example, in U.S. patent application Ser. No. 10/171,358 filed Jun. 11, 2002, which issued on Jun. 10, 2008 as U.S. Pat. No. 7,383,871 and entitled Equalizing Connector for Window Covering Pull Cords, which is of common ownership with the present application.
The present invention has been made to further simplify a cord lift system for a retractable covering so the bottom rail can be conveniently leveled relative to the top rail.